<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>读取</title>
</head>
<body>
    <input type="file">
</body>
<script>
    function read() {
        var input = document.querySelector('input');
        var file = input.files[0];
        var reader = new FileReader();
        reader.onload = function(evt) {
            console.log(evt.target.result);
        };
        reader.readAsArrayBuffer(file)
    }
</script>
</html>